Mitosis
is the process by which a cell ensures each daugher cell will
have a complete set of chromosomes. There are five key stages
of mitosis: During prophase the
chromosomes become condensed and key proteins begin to bind
the the kinetochores, preparing for spindle attachment. Upon
nuclear envelope breakdown, the cell enters prometaphase,
during which the mitotic spindle is formed and the chromosomes
attach to microtubules in the spindle via their kinetochores.
Once attached, the chromosomes start to allign along the metaphase
plate in the center of the spindle. During metaphase,
all of the chromosomes are attached to microtubules via their
kinetochores, and alligned at the metaphase plate. At anaphase
onset, the sister chromatids separate and are moved toward the
poles of the spindle. The chromasomal separation and movement
toward the poles is called anaphase A. The spindle poles separate
as well, which is referred to as anaphase B. Midzone complex
formation also occurs in anaphase. During telophase,
the mother cell is physically divided into two daughter cells
by cytokinesis.